Quote from: bbreconomy on October 05, 2015, 11:06:08 AM

Signing bitcoin transactions offline is really important to a lot of people.

Are there any CryptoNote coins that have made progress with this yet?

https://github.com/monero-project/bitmonero/issues/354

Crosspost because relevant. I'll not clutter the chess game any further :-P

Quote from: dEBRUYNE on October 05, 2015, 08:43:18 PM

Quote from: MoneroMooo on October 05, 2015, 03:07:42 PM

Quote from: dEBRUYNE on October 05, 2015, 02:51:47 PM

MoneroMooo has been working on it in his own branch, but since it is not merged yet it probably isn't finished. See -> https://github.com/moneromooo-monero/bitmonero/commits/cold and in particular this commit: https://github.com/moneromooo-monero/bitmonero/commit/3c44e9fb6c1b57852d37780414ed6e42afc19afb

Quote

This change adds the ability to create a new unsigned transaction from a watch only wallet, and save it to a file. This file can then be moved to another computer/VM where a cold wallet may load it, sign it, and save it. That cold wallet does not need to have a blockchain nor daemon. The signed transaction file can then be moved back to the watch only wallet, which can load it and send it to the daemon.

Two new simplewallet commands to use it:
sign_transfer (on the cold wallet)
submit_transfer (on the watch only wallet)

The transfer command used on a watch only wallet now writes an unsigned transaction set in a file called 'unsigned_monero_tx' instead of submitting the tx to the daemon as a normal wallet does. The signed tx file is called 'signed_monero_tx'.

It worked, though I'm not sure it still applies, though any conflicts should not be hard to solve, if there are any.
What needs doing there is reducing the size of the exchange files, as they're a complete set of transactions plus relevant data, which means the whole deserilization code on the cold wallet is an attack surface. Cutting the size down will apparently make it easier to transfer via QR code scanning, avoiding attacks via filesystems and removable media firmware.

But it works